Colonization and infection with Enterococcus faecalis in intensive care units: the role of antimicrobial agents

Abstract

We studied the influences of antimicrobial agents on the colonization of the respiratory tract and infection with Enterococcus faecalis in intensive care unit (ICU) patients receiving mechanical respiration for at least 3 days. In a matched-cohort analysis, patients receiving topical antimicrobial prophylaxis (TAP) of the oropharynx and stomach with antimicrobial agents not treating E. faecalis were compared with patients not receiving TAP. Patients were matched with controls on the basis of their duration in the ICU, their use of systemic antibiotics treating and not treating E. faecalis, the administration of TAP, their APACHE II score, and surgical procedures they had undergone. In all, 276 patients were analyzed. The colonization of the oropharynx and/or trachea by E. faecalis at admission was demonstrated for 43 patients (16%). Twenty patients (9%) acquired tracheal colonization and 91 patients (40%) acquired oropharyngeal colonization with E. faecalis. In the matched-cohort analysis, 43 patients receiving TAP were matched to two controls each. TAP patients more frequently acquired tracheal colonization (15 of 43 versus 2 of 86 patients, P < 0.00001) and infections with E. faecalis (6 of 43 versus 1 of 86 patients, P < 0.01). The use of topical antibiotics not treating E. faecalis increased the risk for colonization and infection with E. faecalis.Enterococci have become a significant cause of nosocomial infections in recent years (6,17). According to the National Nosocomial Infection Surveillance Survey, which was based on studies in U.S. hospitals between 1986 and 1989, enterococci were the second most common type of microorganism recovered from nosocomial infections (6). In addition, other recent studies have demonstrated the pathogenic potential of enterococci, despite the general assumption that these microorganisms are second-rate pathogens belonging to the normal human flora (8, 9, 15). The genus Enterococcus can be divided into several species, of which Enterococcus faecalis and Enterococcus faecium are most important (19).An increasing incidence of enterococcal infection in recent decades, as reported by some, has been related to an increased use of broad-spectrum antibiotics, especially second-and thirdgeneration cephalosporins (18,20). These agents lack activity against enterococci and may provide the microorganism with a selective growth advantage. Many regimens used for the selective decontamination of the digestive tract (SDD) include a short course of administration of systemic cephalosporins (22). Furthermore, colonization and infection with enterococci might be stimulated by topical antimicrobial prophylaxis (TAP) directed against gram-negative bacteria and Staphylococcus aureus but not against enterococci. For instance, the regimens commonly used for SDD generally do not include drugs that treat enterococci in their antimicrobial spectrum (22). An association between the use of SDD and an increase in the incidence of enterococcal infections has been reported (5, 7, 10, 21), although others ...

Frequent Transmission of Enterococcal Strains between Mechanically Ventilated Patients Treated at an Intensive Care Unit

“…Few data are available for comparison. Bonten et al (2) demonstrated in a study from 1995 that 16% of patients admitted to an ICU were colonized with E. faecalis in the oropharynx and/or trachea at admission. The higher initial rate of E. faecalis colonization in the present study (55%) might be due to the fact that the time point for admission and intubation sometimes do not coincide.…”

Enterococcal-associated Lower Respiratory Tract Infections: A Case Report and Literature Review

“…Feeley et al [7] have found just a single case (0.3%) of pneumonia caused by E. faecalis among 292 patients in an intensive-care unit, who received polymyxin B aerosol in an attempt to prevent P. aeruginosa pneumonia; That patient had died, but the manuscript did not discuss the attribution of the pneumonia to his mortality. Bonten et al [8] reported of 6 patients with ventilator-associated pneumonia, in which E. faecalis had presumably taken a major etiologic role. These patients were part of a group of 61 patients, whose ages ranged from 58 to 79 years, who were given topical antimicrobial prophylaxis for the oropharynx and stomach; E. faecalis, accompanied by another pathogen in each case, was found in cultures obtained by protected-specimen-brush technique and bronchoalveolar lavage.…”

Interplay between the Gastric Bacterial Microbiota and Candida albicans during Postantibiotic Recolonization and Gastritis

“…This bacterium, especially E. faecalis (the predominant species isolated from our treated mice), is a major concern in critical care settings, both due to its pathogenicity and to concern regarding antibiotic resistance (6,7,35,40). Enterococcus is well adapted to survival along the mucosa: it can adhere to different epithelial and extracellular matrix proteins (13) and survive in a broad range of pH environments (29).…”